Tool for engraving rollers applicable for the treatment of photographic films



Oct. 8, 1929. osw 1,730,942

GRAVING ROLLERS APP ABLE FOR TOOL FOR EN THE TREATMENT OF PHOTOGRAPFILMS Filed Dec. 3, 1927 2 Sheets-Sheet l Oct. 8, 1929. osw 1,730,942TOOL FOR ENGRAVING ROLLERS APPLICABLE FOR THE TREATMENT OF PHOTOGRAPHICFILMS Filed Dec. 3, 1927 2 Sheets-Sheet 2 6 l 5 2 1 lb im GawaldPatented Oct. 8, 1929 UNITED STATES PATENT OFFICE ANDRE OSWALD, OFPARIS, FRANCE, ASSIGNOR TO LA SOCIETE DU FILM EN CO'ULEUBSKELLER-DORIAN, 0F FRANC'E TOOL FOR ENG-HAVING ROLLERS APPLICABLE FOR THETREATMENT OF PHOTOGrRAIPHIC FILMS Application filed December 3, 1927,Serial No. 237,525. and in France December 3, 1926.

The present invention relates to improvements in the tools for carryingout the process disclosed in the patent to Audibert No. 1,625,586 ofApril 19, 1927.

The parent invention relates to a mode of obtaining engraved cylindricalsurfaces for the purpose of impressing with accuracy microscopicimbricated refracting elements on the face opposite to the emulsion ofsensitized films used for colour photography. These elements must beperfect optically that is to say, they must present at the apex of theirprincipal section a constant curve for an equal thickness of films thissection being circular or preferably hyperbolic. The entire surface ofthese elements must be highly polished. The production of the engravedcylinders depends upon the pressing back of the face of the saidcylinders which are per fectly smooth and brought to a specular polishby means of a tool likewise brought to a specular polish and of such ashape that the base of the impression itself preserves a specularpolish.

The present invention consists in detail improvements in the tools andmachines used for engraving the cylinders.

In the accompanying drawings:

Fig. 1 is a view of the tool point or extremity forming .the primaryfeature of this invention;

Fig. 2 is a similar view showing a modified curvature for the operativeface of the tool;

Figs. 3 and 4 are modified forms of tool heads wherein the operatingsurfaces are hyperbolic in shape as distinguished from the cylindricalshape in Figs. 1 and 2;

Fig. 5 is a diagrammatic view of the mount ing of the tool in relationto cylindrical surface which is to be embossed;

Fig. 6 is a plan View of the arrangement shown in Fig. 5;

Fig. 7 is an enlarged view of showing more in detail the mounting of therotatable support for the tool head; and

Fig. 8 is a plan view of a modified construction in which guiding meansis provided for the tool holder.

'In order to obtain on the cylinder channels which are perfectlypolished it is necessary inthe first place that the tools should be muchharder than the material of Which the cylinder is constructed so thatthe tool is not subjected to wear on appreciable.deformation. The toolis therefore shaped in the form of a small cutting wheel or of a head ofhard steel or of a stone such as the diamond, sapphire and the like.

In this latter case this head may be either cylindrical (Figures 1 and2) with a right section appropriate to the right section of the grooveto be traced upon the cylinder or else of hyperboloidal shape withappropriate section "(Figures 3 and 4).

In the case of the employment ,of a small cutting wheel which is givenas an example in the parent specification, this cutting wheel must turnwith suflicient friction on its axis, if it is loose on this axis, orturn at a speed adjusted so that itdoes not simply roll on the cylinderbut that it exerts a. frictional effect on the cylinder.

In all cases the tool must be pressed upon the surface of the cylinderand must have no lateral play such as would cause a displacementperpendicular to the path traced on the cylinder. For this purpose, forexample, the engraving tool 1 is mounted on a carrier 2 which canoscillate round an axis 3 (Figures 5 and 6). The pressure exerted by thetool on the surface of the cylinder may thus be regulated to anyrequired extent by means of a spring at or simply by the weight of the,carrier 2. Further the eye of the carrier and the surface of thecylindrical axis 3 must engage perfectly in order to prevent any type ofplay in the oscillation of the carrier.

It is also possible to obtain oscillations which are perfectly free fromplay by the arrangement shown in Figure 7. The axis of oscillation ofthe carrier 2 terminates in conical points 5 absolutely regular andturning in pivots 6 of hard steel or ruby, sapphire or the like, mountedin two supports 6 the distance between which ma be regulated in thedirection of the arrows '--Z. V

Figure 8 represents a modification of the apparatus designed'to obviateany risk of play and of lateral vibration. A rigid arm 8 prolongs thecarrier so that the axes of symmetry or" the arm and of the carriercoincide. This arm 8 carries at its end a point 9 compelled during"working to follow a more or less deep groove of the required iormtraced in a second guide cylinder 10.

The point 9, which is free to move in the direction of the depth of thegroove, will control the engraving point 1 to an extent depending uponthe length ofthe rigid arm 8.

he plastic substance constituting the support of the film when pressedas far as possible by cylinders thus prepared, will take at once thecurvature and thespecular left by the engraving tool.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatWhat I claim is In combination, a rubbing tool for embossing polishedsurfaces comprising ,a rigid head having a hard highly polishedoperating point, a support for said tool including a carriage and anextension arm, and guide means coacting with said extension arm todetermine the movement of the carriage and operating tool.

In testimony whereof I affix my signature.

ANDRE GSWALD.

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